G'Day,
I have the same 1891 long rifle with gain twist circa 1918.
creek conversion E and 3 heavy punches..........its 6,5x54mmM.S. I shoot 6,5x52mm carcano and 6,5x54manlisher sch. out of it......no issues. In actual fact,there is JUST OVER I mm difference.
I HAVE SHOT ''NORMA, and CIL,factory loads plus handloads as well as x52 handloads .
I posted back in NOVEMBER and DECEMBER 2016 about it
Its not a CARCANO you see every day........ fun to shoot 100 year old war horse. WC